This should sum it up:
.............................................Whites MX7.......................Whites MX Sport
Detector Type.......................ground detector.................ground and underwater detector
Technology...........................VLF Single Frequency.......VLF Single Frequency
Number of Frequencies.......1.........................................1
Frequencies.........................13.9 kHz.............................13.9 kHz
Discrimination.......................Adjustable..........................Adjustable
Target Id (VDI)......................Yes, 0-99............................Yes, 0-99
Target Id Segments...............20.......................................20
Programmable Target Id........Yes.....................................Yes
Search Modes .......................7.........................................7
Search Mode Types...............All Metal, Beach,................All Metal, Beach
...............................................Coin / Jewelry, High...........Coin / Jewelry, High
...............................................Trash, Prospecting,............Trash, Prospecting,
...............................................Relics..................................Relics
Ground Balance.....................Automatic, Fixed.................Automatic, Fixed
Threshold...............................Adjustable...........................Adjustable
Pinpoint Mode........................Yes......................................Yes
Audio Tones...........................Yes, 20................................Yes, 20
Volume Control.......................Yes......................................Yes
Battery Type............................8 AA....................................8 AA
Battery Life (hr).......................20+ Hours...........................20+ Hours
Display Type...........................LCD.....................................LCD
Backlit Display.........................Yes......................................Yes
Depth Indication......................Yes......................................Yes
Interchangeable Headphones.Yes......................................Yes
Headphone Jack.....................1/4″......................................1/4″
Adjustable Shaft......................Yes......................................Yes
Assembled Length Min (in)......41........................................45
Assembled Length Max (in).....50........................................55
Arm Rest..................................Adjustable...........................Adjustable
Arm Rest Strap........................Yes.......................................Yes